class Container {
    static of(val) {
        return new Container(val)
    }
    constructor(val) {
        this._val = val
    }
    map(fn) {
        return Container.of(fn(this._val))
    }
}

class Maybe {
    static of(x) {
        return new Maybe(x)
    }
    isNothing() {
        return this._val === null || this._val === undefined
    }
    constructor(x) {
        this._val = x
    }
    map(fn) {
        return this.isNothing() ? this : Maybe.of(fn(this._val))
    }
}
module.exports = {Maybe ,Container }
